R. Xiang, and J. Neville. Proceedings of the Sixth ACM International Conference on Web Search and Data Mining, page 647--656. New York, NY, USA, ACM, (2013)
S. Jeffery, M. Franklin, and A. Halevy. Proceedings of the 2008 ACM SIGMOD international conference on Management of data, page 847--860. New York, NY, USA, ACM, (2008)
T. Malone, R. Laubacher, and C. Dellarocas. Research Paper, No. 4732-09. MIT, Sloan School of Management, Massachusetts Institute of Technology, Cambridge, MA, USA, (February 2009)